Retarder mechanism for conveyor systems



Dec. 29, 1964 M. l. BRENNER RETARDER MECHANISM FOR CONVEYOR SYSTEMS awww/.st

IN VEN TOR. /rsd/ Zferzmer BY- ffl/W Filed April 26. 19Go -i Sb United States Patent O 3,163,260 RETARDER REQHANISM FR CGN VEYR SYSTEMS Marshall I. Brenner, Detroit, Mich., assigner to Anchor Steel and Conveyor Company, Dearborn, Mich., a corporation of Michigan Filed Aprrr, 1966, Ser. No. 24,712

7 Claims. (Cl. 18S- 35) This invention relates generally to conveyor systems, and more particularly to a retarder mechanism for a gravity fed conveyor system.

Conveyor systems are often employed to transport articles between work stations on a production line, or when it is required that articles be stored between work stations or upon completion thereof, to storage or shipping facilities. Often, such conveyor systems comprise, in addition to the conventional power driven section that is driven at a relatively constant speed by one or moreprime movers, a plurality of gravity fed storage sections onto which the articles are shunted for storage. In, for example, an overhead conveyor system, the trolleys thereof `may be Aswitched from the power driven section onto a gravity fed storage line that is inclined at, for example, 'i" to the foot, the trolleys thereafter moving by gravity to the end of the storage line. Such storage lines are often relatively long, for example, 200 or more and, in the absence of a retarder mechanism, the trolleys are free to accelerate therealong until they impact against a stop or the next precedent trolley subjecting the trolley vand the articles carried thereby to damage due to sudden stoppage.

Therefore, the problem presented, to which a retarder mechanism in accordance with the present invention presents a novel solution, is the problem of controlling the velocity of the trolleys as they transverse an inclined conveyor system under the imluence of gravity.

Another requirement of such a gravity fed conveyor system, which in effect is the antithesis of the aforementioned requirement of a retarder mechanism, is established by the practice of unloading the trolleys in succession from the lower end of each storage line, it therefore being necessary that each of the trolleys advance in the line as the terminal carrier is removedtherefrom. Movement of the trolleys must be sutiiciently free so that starting friction of the trolley with respect to the track is easily overcome by the force of gravity.

Therefore, in order to satisfy both of the tioned seemingly incompatible requirements, a retarder mechanism must provide for intermittent free movement of the articles or trolleys along the storage line under the force of gravity, as well as control the velocity thereof, after initial acceleration.

One conventional method of retarding forward movement of the trolleys of an overhead conveyor system is to provide a plurality of drag arms spaced intermittently along the storage line to engage each trolley and thereby exert a frictional drag thereupon as the trolley moves past the arm. Such retarding mechanisms are not entirely satisfactory in that in actual practice the loads carried by the trolleys vary considerably. A heavily loaded trolley may pass the drag arm without being material decelerated. On the other hand, a lightly loaded trolley may not have suftcient inertia to pass beyond the drag arm. Also, if a trolley happens to stop in contact with the drag arm the gravitational force tending to move the trolley may not be suiiicient to overcome both the starting friction of the trolley and the holding friction of the drag arm.

The retarder mechanism of the present invention intermittently retards and releases the trolleys of a conveyor aforemen- ICE system thereby to control acceleration thereof. This concept is embodied in a retarder mechanism thatgprefer ably extends the entire length of the gravity fed section of a conveyor system and comprises a plurality of brake shoes that are connected for concomitant operation so as'to be intermittently engageable with the trolleys to control the velocity thereof. The retarder mechanism has a plurality of adjustments that provide for positive control over the braking forces irrespective of load or the location of the trolleys on the gravity fed storage line.Y When -paralleled gravity fed conveyor lines are utilized, the retarder mechanisms thereof can be energized byv a common power source. f

Accordingly, one object of the present invention is an improved retarder mechanism for a conveyor system.

Another object is a retarder mechanism that is intermittently engaged and released to elect positive control of the velocity of an article moving along the conveyor system.

Another object is an intermittently operable retarder mechanism having provision for adjustment of the fre` quency of engagement thereof with an article supported for movement by the conveyor system.

Another object is a retarder mechanism that isv easily adjustable with respect to the engaging bias thereof on anarticle carried by the conveyor system.

Another object is a retarder mechanism that is compatible with conventional conveyorl systems.

Another object isa retarder mechanism having a plu.

rality of brake shoes extending substantially the entire length of the conveyor system.

Another object is a retarder mechanism for a conveyor system that is easily paralleled with similar retarder mech# anisms on aligned gravity fed conveyors. Y

Other objects and advantages of the presentinvention will become apparent from a study of the following specification wherein reference is made to the drawings in which:

FIGURE 1 is a fragmentary side elevational view of a retarder mechanism shown in operative-association with an overhead conveyor system; Y

FIG. 2 is a fragmentary view of the portion designated 2 of FIGURE 1 enlarged for clarity;v

FIG. 3 is a cross-section view taken substantially along the line 3 3 of FIG. 1;

FIG. 4 is a cross-section View taken substantially along the line 4 4 of FIG. 3; and Y FIG.'` 5 is a top-plan View of a plurality of retarder mechanisms operatively associated with a like plurality of overhead conveyors, the retarder mechanisms being energized by a common power source.V

A retarder mechanism 10, in accordance with an eX- emplarytembodiment ofv the present invention, is shown in operative association with a conventional track 12 of an overhead conveyor system. The track 12 is formed by two opposed anges 14 and 16 on an L-shaperl beam 18 and a U-shaped channel 19, respectively, that are spaced to accommodate a trolley 20 therebetween. The opposed horizontally extending anges 14 and 16 on the beam 18 and channel 19, respectively,l support a plurality of suitably spaced wheels 22 of the trolley 20. The beam 18 and channel 19 are supported at spaced intervals by suitable hangers 28 that are suspended as by suitable rods (not shown) from the superstructure of an enclosure.

Each of the retarder mechanisms lll is similar in con-s struction, therefore, for the purpose of clarity, only onewill be described hereinafter. Also, because each retarder mechanism 10 comprises a plurality of longitudinally aligned and interconnected brake sections of similar construction, only one brake section will be described, like Patented' Dec. 29, 19641 l supported 4by .the upstanding brackets 92.

areaseo numbers being applied to'like elements of each brake section.

Each brake section of each retarder mechanism gitudinal yand vertical movement with respect to the trackv 12 by slidable engagement of the tange 32 thereof be?` 'tween a vertical ange on'the L-shaped beam 18 and a guide flange 38 that is secured to the inner face of the flange 3 6 on the beam 18, as by welding. v

4' thereby moving the brake shoe 3i) in translation upwardly and to fthe right, as seen in the drawing, with respect to the track 13 as the connecting rod 1&3 moves to the left. As the connecting rod 188 moves to the right, Vthe brake shoe 3i? moves downwardly and to the left, whereupon the brake lining 65B thereon engages the wheels 22 of the trolley 2t).V y

1t is to be noted that the extensibility ofthe connecting rod 108 provides for the initial positioning of the brake shoe St) with respect to the track 12, and is so adjusted that the brake shoe completely clears the wheels 22 of A brake lining of suitable material, forV example,"

. cloth reinforced asbestos, is affixed to the horizontal ange etfectmovement of the retarder mechanism 1?, as will be described. The hanger 66 has a pair of transversely extending pins 84 and 86 for pivotal support of a rear pivot Y arm 8S and the other end of the tie bar 78, respectively. The pivot arms Si? and S8 and bellcrank S2 are pivotally supported `on pins 9! that extend transversely of a like number of upstanding pivot arm support brackets 92.

The arm support brackets 92 are secured to appropriate ones of the ltrackhangers 2S, as byweld-ing.

One of the brake shoes3l is mechanically connected to avvariable speed electric motor 91` (FIG. 5), in a manner to be described, to effectV concomitant movementof the plurality of aligned and interconnected brake shoes 3) that comprise each retarder mechanism 1li.

A pair of spaced bearing support brackets 10i) and 101 are secured to and extend` between spaced ones of the Vhangers 2S. A pair of bearingsltZ and 103 are supported on lthe brackets 169 and 1691, respectively, so as to journal atransversely extending drive shaft 104.' The drive 194 is connected to the electric motor 91 through a suitable speed reducer y165.' A circular cam 1% is eccentrically mounted on the drive shaft to effect reciprocation of a connecting rod 198 that is rotatably connected about the eccentric cam 106. An end portion 1119 of the connecting rod 198 is threadably engaged with one end of a tubular coupling 112, relative rotation therebetween varying the additive length of the coupling 112 andconnecting rod 1&3. A threaded rod is engaged with the opposite end of the tubular coupling112 and extends into a central bore 114 in a t tubular member 13). The rod 120 is connected to the member-.130 by a helical coil spring 132 that extends between a nut 134 on the rod 120 and one side ofra transverse collar 136 on the end of the tubular member 13%.

A nut 137 is threadably engaged with the rodlZt) and with the other side of the collar 136. Thcrefore`-axial movement of the rod 12@ to the left, as seen in the draw`` ings, is transmitted to the member 13d by the nut 137.

Axial movement of the rod 129 to the rightis transmitted to the member through theV spring 132.

An end plug 140 on the tube 13) has a'transverse pin 142 extending therethrough for the pivotal support of an upper end portion 144 of the downwardly extending bellcrank 82. The bellcrank 82 is pivoted on an appropriate one of the transversely extending pivot pinsV 9) that are The bellcrank has ak downwardly depending portion 145 for connection Y to the drive pin 76 on the brakeshoe 3b.

Rotation of the drive shaft 164 and eccentric cam V1% rotating the bellcrank 82 about itsA pivot Qd'with an' oscillating motion. Oscillation of the bellcrank .S2 is'trans mitted to the brake shoe 36 through the drive pin 76 the trolley 2t? when driven to the upper position. Thereafter the lost motion linkage through the spring 132 provides for controlled frictional engagement between ,the brake 3l? and the trolley 2).- Thebraking eifect of the oscillating brake shoe 3G on the trolley 20 can becontrolled by either varying the additive length of the coupling 112 and connecting rod 168, by increasing the pressure of the brake shoe 30 on the trolley 2) by changing Ythe initial bias of thespring 132 or by varying the rota-v .tional speed of the drive shaft 164' thereby to vary thev number of contacts per minute of the brake shoe 30 with the trolley 20. The first two of the aforementioned adjustments are mutually interdependent, the latter adjustment being independent of the others. In this manner the retarding elfect yof the mechanism 1) can be, both initially adjusted to meet an anticipated conditionand controlled while in operation byrvarying the speed'y Qf'the invention isr susceptible to modification, variation and change without departing from the proper scope .or fair meaning of the subjoined claims..

What is claimed is: l. In a gravity fed conveyor system, including a track with a Wheeledtrolley thereon, a retarder mechanism for kcontrolling the velocity of; movement of the trolleyalong the track comprisinga brakeshoe pivotally supported at ,twospaced points for movement in translation toward and away from said track and frictionally engageable with the trolley upon movement toward the track, a bellcrank supported for rotation by said track and pivotally engaged with said brake shoe and a free end of a connecting rod, a cam journaled in the other end of said connecting rod, and a drive shaft extending eccentrically throughsaid cam whereby rotation of said drive shaft elfects reciprocation of said connecting rod, bellcrank and brake shoe thereby to effect intermittent engagement and disengagement of said brake shoewith said trolley.

2. In a gravity fed conveyor system including a track with a Wheeled trolley thereon, a retarder mechanism for controlling the velocity of movement of the trolley along the track comprising abrake shoe pivotally supported at two spaced points for. movement in translation toward and away from said track and frictionally engageable with the trolley upon movement toward the track, a bellcrank supported for rotation by said track and pivotally engaged with said brake shoe and an extensible connecting rod, a cam for driving said connecting rod, and a drive shaft eX- tending eccentrically through said cam whereby rotationV of said drive shaft el'ects reciprocation of said connecting rod, bellcrank'and brake shoe thereby to effect intermitf :tent engagement and disengagement of said brake shoe With said trolley. i

3. In a gravity fed conveyor system including a track with a wheeled trolley thereon, a retarder mechanism for controlling the velocity of movement of the trolley along the track comprising a brake shoe pivotally supported at two spaced points for movement in translation toward and away from said track and frictionally engageable with the trolley =upon movement toward the track, a bellcrank supported for rotation by said track and pivotally engaged with said brake shoe, resilient means connecting said bellcrank and connecting rod, a cam for driving said connecting rod, and a drive shaft extending eccentrically through said cam whereby rotation of said drive shaft effects reciprocation of said connecting rod, bellcrank and brake shoe thereby to effect intermittent engagement and disengagement of said brake shoe with said trolley.

4. In a gravity fed conveyor system including a track with a wheeled trolley thereon, a retarder mechanism for controlling the velocity of movement of the trolley along the track comprising a brake shoe pivotally supported at two spaced points for movement in .translation toward and away from said track and frictionally engageable with the trolley upon movement toward the track, a ange on said brake shoe slidably engageable with said track to guide relative movement therebetween, a bellcrank supported for rotation by said track and pivotally engaged with said brake shoe and one end of a lost motion linkage, resilient means connecting the other end of said linkage with one end of a connecting rod, and compressible upon movement or" said connecting rod in one direction, rigid means on said connecting rod engageable with said linkage to positively drive said linkage upon movement of said connecting rod in the other direction,` a cam journaled in the other end of said connecting rod, a drive shaft extending eccentrically through said cam, and a variable speed prime mover for etecting rotation of said drive shaft whereby rotation of said drive shaft eects reciprocation of said connecting rod, bellcrank and brake shoe thereby to elcect intermittent engagement and disengage- Vment of said brake shoe with said trolley.

5. In a gravity fed conveyor system including an elongated inclined track and a trolley continuously movable along the track, a retarder mechanism for controlling the velocity of movement of the trolley ongthe track comprising a brake shoe, means normally supporting said brake shoe in spaced relation to said track and trolley for moving said shoe into frictional engagement with saidtrolley, and an electric motor connected to said means operable to effect movement of said brake shoe into and out of engagement with said trolley in a predetermined continuing sequence thereby to alternately slow the continuous movement of said trolley then release said trolley for movement due to gravity. Y

6. A gravity fed conveyor system in accordance with claim 5 wherein said supporting means includes means for regulating the pressure exerted by said brake shoe against Said trolley. *Y v 7..A gravity fed conveyor system in accordance with claim 5 wherein the speed of said electric motor is variable so as to vary the time lapse between successive en-` gagements of said brake shoe with said trolley.

leerences Qited in the tile. of this patent UNlTED STATES PATENTS Canada July 21, 

1. IN A GRAVITY FED CONVEYOR SYSTEM INCLUDING A TRACK WITH A WHEELED TROLLEY THEREON, A RETARDER MECHANISM FOR CONTROLLING THE VELOCITY OF MOVEMENT OF THE TROLLEY ALONG THE TRACK COMPRISING A BRAKE SHOE PIVOTALLY SUPPORTED AT TWO SPACED POINTS FOR MOVEMENT IN TRANSLATION TOWARD AND AWAY FROM SAID TRACK AND FRICTIONALLY ENGAGEABLE WITH THE TROLLEY UPON MOVEMENT TOWARD THE TRACK, A BELLCRANK SUPPORTED FOR ROTATION BY SAID TRACK AND PIVOTALLY ENGAGED WITH SAID BRAKE SHOE AND A FREEE END OF A CONNECTING ROD, A CAM JOURNALED IN THE OTHER END OF SAID CONNECTING ROD, AND A DRIVE SHAFT EXTENDING ECCENTRICALLY THROUGH SAID CAM WHEREBY ROTATION OF SAID DRIVE SHAFT EFFECTS RECIPROCATION OF SAID CONNECTING ROD, BELLCRANK AND BRAKE SHOE THEREBY TO EFFECT INTERMITTENT ENGAGEMENT AND DISENGAGEMENT OF SAID BRAKE SHOE WITH SAID TROLLEY. 